Chemicals React
by UnchartedHeart
Summary: AU. When the brainy scientist Tifa tests one of her experiments, things began to change along with her emotions. How will her down to earth boyfriend, Reno, handle it...and fix it? ReTi. Written for The Sacred and Profane. M for Language.


A/N: Here's another ReTi for The Sacred and Profane! Hope you all like it! This reminds me though, if anyone would like a request written for them, just PM me! I enjoy doing it! Thanks!

Disclaimer: ……whatever.

* * *

Reno followed the secretary as she led him back to the lab where his girlfriend, Tifa Lockhart, was working; working late, at that. Ever since the brunette came across a new idea, she was working late nights in the lab, leaving no extra time for her love life or any other kind of life. Reno, as patient as he was being, decided to change things up a bit and check on her that night.

The secretary led him through corridors of white hallways, the bright florescent lights beaming down against his red hair. He had always joked about how the office looked like a secret agent building. The thought of it made him laugh quietly to himself. They finally made it to the large steel doors that inhabited the lab behind them. The secretary scanned them through and opened the door for Reno. The redhead gave her a wave of thanks and she held a hand up.

"Now listen, don't touch anything, don't mess with anything and don't eat anything. Those are the rules. Visit your girlfriend and get out, is that clear?" the secretary stated in a whiny voice. Reno rolled his eyes and nodded, walking into the domain of the science lab. The door closed behind him with a hiss and he strolled through the many test tubes, tanks and whatever else was in there, to finally find his girlfriend, hunched over paperwork, whispering to herself.

Reno smirked as he pulled his hands out of his jean pockets and wrapped his arms around her from behind, startling the scientist. Tifa dropped her glasses, jumped, and turned in Reno's arms to face him. A sigh a relief left her lips as she smiled.

"Just what are you doing here, sweetie? Do you know what time it is?" she asked. Reno shrugged and kissed her.

"Who cares…I missed you. I'm ready for this new project to be done so we can have some alone time again." Reno replied, pulling her close. Tifa kissed him back and wriggled out of his arms to continue her work.

"Well…we're on the last leg here. I just have to test this contraption to see if it will work. If correct, it can possibly cure bipolar disorder!" the brunette beamed at him, holding out the test tube for him to see. A crimson eyebrow raised and he tapped the jar.

"Congratulations Tifa baby, I think you just created a new color. What the hell is that?" he asked, examining the strange colored liquid in the tube. Tifa laughed and shook her head.

"It's just Argon combined with Phosphorus and Selenium. It turns it from a metal to a non-metal with just two elements and the concoction should clash the chemicals together to create a simple antibiotic." She mused, as if it were the most obvious thing in the world. Reno however, looked at his girlfriend as if she were speaking another language. That was one thing that the redhead left alone; Tifa's ability in the scientific field. She was a mark of pure genius, while Reno held a job at the bank as a computer manager. Both complete opposites. Tifa was the intellectual, Reno was the happy go lucky, goofy guy. In his eyes…they were perfect for each other.

"Right…well, how do you plan to test it, babe?" he asked, leaning against the table she was working from. Tifa bit her lip and looked around.

"I have no idea...I guess I could try it." She suggested slowly, raising the liquid to her lips. Reno stopped her suddenly, his eyes widened like saucers.

"No! Are you crazy! What if it killed you, Teef?" he yelled out, his voice echoing in the lab. Tifa winced at his words and shook her head sharply.

"Stop being a diva, Reno. It's for the good of science. Trust me, I'll be fine!" she insisted, not giving the chance for Reno to intervene as she took a rather large sip of the odd colored liquid. Reno closed his eyes tightly and waited for sounds of pain or agony. Nothing came. Nothing happened.

"W-what? It…it didn't do...anything…did it?" Tifa stammered, a little disappointed from the outcome. Reno was relieved and held out a hand for his brainy girlfriend.

"That's okay baby, it's just a sign that you need some rest. Your brain is tired. C'mon, let's go home and I'll run you a bubble bath and crack open some champagne. Then we can…you know…really relax." The redhead offered, his lips turning up into that same lopsided smirk he always gave when he was suggesting something sexual. Tifa giggled and took his hand, grabbing her purse and shutting the lab lights off before they left.

* * *

Once they reached their townhouse, Reno got to work on the things he had promised. He turned on the hot water, letting the lavender bubble bath soak into the water while he dashed to the wine cooler for some of the best champagne that they owned. He found a bottle and opened it, pouring some in a flute to give to Tifa, who was slipping into the heated bath with a loud sigh.

"Here you are doll, just how you like it." He whispered, setting the glass on the ledge on the tub so she could drink it. She pulled the redhead down for a kiss and winked at him before she sank lower.

"I can't believe it didn't do anything though, Reno…I really needed a big break with that medicine. I've worked so hard…I hope I don't get fired…" the brunette complained from the bathroom, her stammering voice echoing off the walls. Reno was sitting on their bed, listening to her with confusion. She sounded as if she were about to cry. He sighed and got ready to get up.

"Tifa, again…if you don't relax, you're not going to get anywhere. Maybe it's because you've been working too hard, you know? These late nights and all." He explained, standing up. Tifa must've sensed her boyfriend's presence, because she stood up in the tub only to scream at her reflection in the mirror.

"Oh my…my…GOD! HAIR!" she screamed, Reno rushed into the bathroom.

"Yes Tifa, you have….oh…shit." he stated, his jaw dropping. Tifa turned to look at Reno, a dark beard growing on her jaw line. She cried even more and buried her face in her hands. Reno thought quickly and pulled Tifa into his arms, ignoring the scratchy feeling of her new hair.

"Baby, it's…not that bad, okay? I mean we can figure something out! Don't cry…"

"B-But it looks awful! No, terrible! I can never show my face to the world again, R-R-Reno! It must've been that experiment I drank! It...it did this to me!" she cried, yanking at the hair on her face. Reno did the most outrageous thing he ever thought possible in such a situation, he laughed.

Tifa looked up at her boyfriend as if he were the craziest person alive. She didn't know whether to slap him, or ask him what the hell he was doing. For the strangest reason though, she felt like laughing too. Suddenly, the scientist broke into numerous bits of laughter. They continued this for a few moments until Reno halted and pointed at Tifa.

"It's gone! Tifa look!" he stated. Tifa gasped and rushed to the bathroom, coming back out with a smile on her face.

"I guess it di-" she began, only to be cut off by a jolt. She looked up to see Reno staring down at her with wide aqua hues, still pointing at her.

"What happened now?" she asked, in a very squeaky voice. Reno picked her up and took her to the mirror in the hallway. Tifa gaped at herself…at her nine year old self. She had shrunk in age!

"This is so strange..." she whispered. Reno set her down and walked back into the bedroom.

"Yeah, you can say that again." He mused, biting his lip.

"Well, it must be that experiment again…it's like…every time my emotions change dramatically…I change along with the emotion!" she squealed, looking down at herself. Reno nodded, understanding what she meant as he rested his chin on his hand.

"Shouldn't we figure a way to change you back?" the redhead suggested. Tifa placed a tiny finger to her lips as she lifted her gaze in thought.

"Hmmm…sure we'll just go to the lab, but…Reno?"

"Yes…?"

"Can we play first?"

"Tifa…why don't we get to the lab?"

"Well…I mean we can soon, I'll be fine right now, just as long as my emotions don't change too much, right?"

"Fine…what would you like to play first…" This was going to be interesting.

* * *

After playing Barbie's, coloring, a game of tag, coloring again, and very long tea party, Reno was about to give out. Little Tifa had played non-stop, while Reno did everything he could to keep her from changing her emotions too much, as tempting as it was. Now, they were engaging in their second go round of playing Barbie's and Reno had decided he had enough.

"Okay Tifa, don't you think we should get to the lab now? It's almost morning…you can't go into work like that." He suggested, rubbing his temples as she dropped the doll she was holding.

"Reno…it's not my fault you're not having fun…I told you to stop being lazy and put clothes on your Barbie! It's better than just leaving it naked…where's the fun in that?" she huffed, picking up his naked doll for emphasis. Reno let out a laugh and smirked.

"Well…there's a lot of fun in being naked, Teef, you oughta know that."

"Stop it! This is Barbie's we're talking about…not us! When I get back to normal, I'll just punish you and refuse!"

"That's if you ever get back to normal. I mean, we're playing around here and you're not even thinking of going back to the lab yet!"

"Oh yeah! Well let's…let's go now, you big poop face!" she yelled in anger. Reno tried to stop her but the jolt happened to soon, causing Tifa to shrink even smaller. She was now smaller than the doll and she looked up at him, her brows furrowed in anger.

"See what you made me do!"

"Whatever, babe, let's just get to the lab, shall we?" Reno stated, sighing in exhaustion as he picked his girlfriend up and cupped her in his hand. He snatched the car keys and made his way out the door.

When they got to the lab, Reno had to sneak in, as he didn't have an I.D. He finally reached the lab and flicked the switch, causing the room to light up with the blinding white lights. He walked over to the metal table, the concoction still sitting in its test tube. The redhead set Tifa down on the table and bent down so he could see her better.

"Alright…what to do I do?" he asked, running his hands through his hair. Tifa rolled her eyes and pointed over to the chemical rack.

"Okay, we need to make a reverse chemical. Go get me some…Beryllium, Iodine and Cerium." She commanded, tapping her small foot in impatience. Reno shifted his eyes and his lips twitched as he walked over to the rack and began reading for the correct chemicals. This wasn't an easy task as he had no idea what he was doing. Computers were his forte, not mixing odd chemicals together. Hell, he had almost failed chemistry. The only way he passed was giving his fat ass teacher a huge cake.

"RENO! Stop laughing and get me those damn chemicals, right now! I hate being tiny!" Tifa squeaked at him. Reno realized he had been laughing out loud and he clamped his lips shut, snatching the right chemicals and walking back over to the table.

"Here you go, shorty." He teased, placing his hands on the table for the next direction. Tifa examined the labels and nodded, giving him the thumbs up.

"Okay, measure 2 millimeters of the Cerium and 1 millimeter of the other ones, got it? It HAS to be precise, Reno, I'm not kidding." She warned, pointing a finger at her boyfriend. Reno was now getting nervous. He grabbed a pair of spare goggles and placed them over his eyes as he began mixing the chemicals exactly how Tifa had told him.

In all honesty, he was anxious as hell. What if he messed up? The thought of accidently killing the woman he loved, scared him. Reno pressed on, however. He finally finished slowly mixing the chemicals, looking back down at Tifa.

"Good, it looks correct, now sprinkle some on me, okay?"

"I…don't know…Teef, I'm not good at this…what if I fucked it up…and it…and it-"

"Reno, stop it! You're fine…it looks right…just trust in yourself. Now, sprinkle some."

"I love you, Tifa…"

"I love you too, Reno…now do it!"

Reno dropped a few tiny droplets on Tifa, clenching his eyes shut as he did so. He was so scared of the outcome. Silence filled the lab for a couple of minutes, neither daring to talk. The redhead's eyes remained shut as he felt soft hands lift his face. He cracked an eye open to see Tifa, back to normal, smiling at him.

"Baby, you did it!" she whispered, pulling him flush to her as she kissed him deeply. Reno broke the kiss and smiled back.

"I'm just glad you're okay…because…well…I'd never get to do this…" he began, pulling out a box and holding it towards the confused scientist. Tifa cocked her head to the side as the idea finally revealed itself in her mind.

"Oh Reno…"

"Will you marry me, my gorgeous, amazing, smart and perfect, Tifa?" he asked, a sheepish smile reaching his lips. Tears filled the brunette's eyes as she jumped from the table to join him on the ground, letting him slip the ring on her finger.

"I will, my amazing, silly, funny and sexy, Reno."

* * *

After leaving the lab and Tifa deciding to take a day off, Reno treated her to a good dinner at her favorite restaurant. Both laughed and reminisced about the situation that they dealt with the day before.

Meanwhile, a fellow scientist and coworker of Tifa's, Yuffie, lurked through the lab.

"Man, I'm thirsty…ohh…what's this?" she asked herself, picking up the odd colored vial. She took a sip and made a face at its strange taste.

"Ew! What a gross concoction!" Yuffie complained as she left the lab. She didn't even notice the tail growing out from her backside.

* * *

A/N: The end!! Hope everyone enjoyed it. Oh yeah and the Chemistry teacher and cake part? I definitely did that…and it got me an A! Gotta love hungry teachers.


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